I agree that your best bet is wash, clay, then an AIO (using a DA). In way simplified terms, you can think of an AIO as a liquid compound and a liquid sealant mixed together and bottled up. I'm sure the manufacturers put a lot of work into mixing just the right chemicals together, so don't think you can just mix 2 products together yourself and make your own AIO, that's just a basic explanation of what an AIO is (to my understanding).
If you do decide to use an AIO, you will need a DA, because the abrasive agents only work if they're rubbed against the paint. A DA will give you something like 400rpm (plus a few thousand oscillations per min). Working by hand, you just won't realistically be able to rub the AIO that much.
You can get a DA, a six pack of pads, clay, and an AIO for right at $200. Get the six pack of pads. It'll take several pads to do a vehicle, and if you're like me, you'll tear up the first few pads trying to learn how to use them. I don't know about other DA's, but my GG came with a 5 1/2" backing plate. I'm a newbie myself, and I've found that working with smaller pads is easier for me than larger pads. I would suggest that when you place your order, you also buy the Lake Country flexible 5" backing plate (it'll cost $10-$15). That way, you can use the pads that are 5 1/2" diameter and 7/8" thick. The only other thing you might consider buying is some good microfiber towels and a good wash mitt. Nothing sucks more than putting in all the work then swirling it up as soon as you run a towel or wash mitt across it. Don't buy cheap microfibers from Autozone or Home Depot or any place like that. They're junk and will mar the paint BAD and I'd rather use a cotton bath towel than those (I learned that the hard way). I always look for a cheaper solution, and I'm not one that thinks name brand is automatically better. I know there are pro detailers on this forum who can run circles around me, and a few of them use cheap microfibers or cotton bath towels. Maybe when I'm more skilled I'll be able to get away with using cheap towels safely, but being a newbie, I've found that if I use a cheap towel, I swirl the paint.
Also, for your clay lube, use ONR or the rinseless wash concentrate that DP makes (whichever is cheaper). That way, you can use it as a clay lube, rinseless wash, or a waterless wash. After trying out ONR, I'll never use a regular wash again (unless the car is super dirty). One thing I don't like about ONR is using it as a QD. It just doesn't feel slick to me, and I'm in love with Meg's QD. Haven't tried Meg's newest QD, but their old QD that had been around forever (in the maroon bottle) is amazing. Personal preference, vets don't bash me.
Alright, now that we added in a backing plate, towels, wash mitt, and a bottle of ONR, I'm thinking your probably looking at around $250, but you will definitely be well under $300, and once you make the investment, you're set for years (since you're only doing your personal vehicles).
This is a lot of info, and it may sound overwhelming, but it's not. Don't let it scare you. The first time or 2 you do your personal vehicle will take up a lot of time (if you're anything like me, but I'm a perfectionist. Plus, I'm not good with my hands. When it comes to book smarts, I'm a genius, but common sense working with my hands kind of things don't come easily to me). Once you've done it a couple of times and get the hang of it, the time required will go down DRASTICALLY. Don't let all this info overwhelm you. Wash, clay, dry, AIO with a DA, you're done. It really is that simple.
A couple of last thoughts. Don't get one of those wax spreaders from Autozone for $30 or $40. I think they may say DA on the box, but they don't work for ANY kind of correction work, so using them with an AIO is pointless. They are great for applying a traditional, non abrasive wax with no correction properties, but that's it. For more info on this, do a search for wax spreader.
IF this is more than you are wanting to do, you could always wash, clay then use a traditional wax by hand, but the swirls are still gonna be there. I really think that if you go with a DA and and AIO, you will be MUCH happier with the results, and I bet your vehicle will look better than any brand new car sitting outside on a new car dealer's lot.